Domestic appliance



Feb. 5, 1957 c. A. STICKEL 2,730,008

DOMESTIC APPLIANCE Filed Sept. 25, 1953 Fig. 2

Carl A. SI/c/re/ His Attorney I N VEN TOR.

United States Patent Q DOMESTIC APPLIANCE Carl A. Stickel, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application September 25, 1953, Serial No. 382,235

4 Claims. (CI. 34-54) This invention relates to a domestic appliance and more particularly to laundry dryers.

Air movement through the clothes carrying drum of a laundry dryer during the first part of the drying cycle tends to carry any dust in the room air into contact with the damp clothes in the dryer. The dust. will stick to and contaminate the damp clothes. It is my opinion, where a condenser is provided, this air movement adsorbs heat and does not substantially assist the initial drying of the clothes since the drying can be accomplished faster through the direct heating and vaporization of the moisture and migration of the moisture without air movement to the condenser through diffusion. Also more moisture can be condensed and less moisture will be discharged into the air in the room. However, as the clothes become more and more dry, the drying rate is improved as an increasing rate of air circulation is provided through the operation of the laws of vaporization under partial pressure. The dust is less apt to stick to the clothes when the clothes are nearly dry.

It is an object of my invention to provide a condenser type laundry dryer with an arrangement whereby there is no air circulation and drying takes place by migration of vapor to the condenser during the first part of the cycle until a substantial portion of the moisture is removed from the clothes and thereafter a gradually increasing air movement from the clothes to the condenser is provided in optimum amounts until the clothes are dry.

It is another object of my invention to provide a condenser type laundry dryer with an air inlet damper arrangement and a means for keeping the inlet damper closed at the start of the drying cycle and gradually opening the damper as the drying progresses.

In the form shown, these objects are attained by providing an air inlet to the drum chamber of the dryer which is closed by a damper. The damper is provided with a bimetal opening means which when cold keeps the damper closed. By the heat provided in the dryer by the usual heating element and/or by heat provided by a separate electric heater under the control of the usual timer for the dryer, the bimetal is gradually heated to gradually open the damper after an initial closed period.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the invention is clearly shown.

In the drawing:

Figure 1 is a vertical sectional view, partly diagrammatic, of a condenser type laundry dryer embodying one form of my invention; and

Figure 2 is an enlarged sectional view of the damper and heating means of the dryer.

Referring now to the drawings and more particularly to Figure 1 there is shown a laundry dryer including the cabinet 20 having an insulated wall 22 enclosing a drum chamber 24. Within the drum chamber 24 there 2,780,008 Patented Feb. 5, 1957 is provided a perforated rotatable drum 26 which may be rotated by the same motor used to drive the fan 28 as is customary in the art. The drum chamber 24 is provided at the bottom with an outlet opening 30. Connecting directly to this outlet opening and extending downwardly therefrom is an air cooled condenser 32 having vertical tubes draining onto a tray support 34 which in turn drains into a collecting basin 36. The cabinet is provided with inlet louvers 38 on the right side of the condenser 32 through which room air enters the cabinet and flows through the spaces between the tubes of the condenser 32. The room air is drawn through the condenser 32 around the vertical tubes thereof by the fan 28 which discharges the air through the outlet louvers 40 on the opposite side of the condenser 32.

At the start of a drying cycle, clothes are placed within the drum 26. The automatic clock type timer 41 is started and energizes the motor of the fan 28 and the electric heater 42 at substantially the same time. The drum 26 is rotated by the fan motor while the fan 28 draws air through the horizontal passages of the condenser 32. The electric heater 42 heats the damp clothes in the revolving drum 26 causing the moisture to be vaporized. This moisture migrates through the air to the condenser 32 where it is condensed in the vertical tubes while they are cooled by the horizontally flowing cooling air from the room. Instead of cooling air, water or any other suitable cooling medium may be substituted.

The cabinet is provided with an air inlet tube 44 adjacent the heater 42 which is normally closed by the damper 46. The damper 46 is operated by a curled bimetal member 43 having its lower end fastened to the damper 46 and its upper end curled about and fastened to the adjustable anchorage 50. The anchorage 50 is so adjusted that when the bimetal 48 is cold the inherent spring of the bimetal resiliently holds the damper 46 in closed position. This will keep the damper closed during the initial portion of the drying cycle. The reflector 43 shields the bimetal 48 from the direct heat rays of the electric heater 42.

The heating of the drum chamber by the heater 42 will cause the bimetal 48 to be gradually heated. After a period of time the bimetal 48 will be heated sufficiently to gradually open the damper 46. .While the damper is closed the major portion of the moisture in the clothes is removed by vaporization due to the heating 'of the clothes and the condensation of the moisture in the condenser. This migration of vapor takes place through diffusion in adequate amounts without any substantial air movement. Since there is no air movement through the drum chamber, substantially no moisture is discharged into the room during this period. As the clothes become more and more dry the drying action is assisted by the air movement through the nearly dry clothes. As the end of the drying cycle is approached the damper 46 is opened wide so that there is ample air circulation to quickly and thoroughly dry the clothes.

If desired, the heating of the bimetal 48 may be assisted or even controlled entirely by the electric heater 52 located immediately adjacent the bimetal 48 and connected by the conductors 54 and 56 to the timer 41. During an intermediate portion of the timer cycle the timer 41 closes contacts connecting the heater 52 with the supply circuit so as to supply an increasing amount of heat to assist in heating the bimetal 48. The reflector 43 may be provided with a backing of thermal insulation 47 when desired to reduce the heat transfer from the heater 42 to the bimetal 48 sufiiciently that the bimetal 48 is substantially entirely under the control of the heater 52 and the automatic clock type timer 41.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come Within the scope of the claims which follow.

What is claimed is as follows:

1. A laundry dryer including a cabinet having a drum casing, a rotatable clothes drum within said casing, heating means for said casing, a condenser having a first set of passages communicating at one end with said casing and a second set of passages separated from but in heat transfer relationship with said first set, an air circulating arrangement comprising fluid inlet means for said casing and fluid outlet means for the second end of said first set of passages, said cabinet having second inlet means communicating with one end of said second set of passages and second outlet means communicating with the other ends of both the first and second sets of passages of said condenser, fan means for drawing air from said other ends of both the first and second sets of passages of said condenser, said air circulating arrangement being provided with normally closed valve means for stopping the flow of fluid, driving means for said drum and fan means, and control means provided with power operating means for opening said valve means after the driving means and heater have operated for a period and the clothes in the drum are partially dried.

2. A laundry dryer including a cabinet having a drum casing, a rotatable clothes drum within said casing, heating means for said casing, a condenser having a first set of passages communicating at one end with said casing and a second set of passages separated from but in heat transfer relationship with said first set, an air circulating arrangement comprising fluid inlet means for said casing and fluid outlet means for the second end of said first set of passages, said cabinet having second inlet means communicating with one end of said second set of passages and second outlet means communicating with the other ends of both the first and second sets of passages of said condenser, fan means for drawing air from said other ends of both the first and second sets of passages of said condenser, said air circulating arrangement being provided with normally closed valve means for stopping the flow of fluid, driving means for driving said drum and fan means, and timing means for first causing the operation of said heater and driving means and after a period of operation of said heating and driving means sufl'icient to cause the partial drying of the clothes by migration of the moisture to the condenser causing the opening of the valve means to circulate air through the drum casing and said first passages.

3. A laundry dryer including a cabinet having a drum casing, a rotatable clothes drum within said casing, heating means for said casing, a condenser having a first set of passages communicating at one end with -said casing and a second set of passages separated from but in heat transfer relationship with said first set, an air circulating arrangement comprising fluid inlet means for said casing and fluid outlet means for the second end of said first set of passages, said cabinet having second inlet means communicating with one end of said second set of passages and second outlet means communicating with the other ends of both the first and second sets of passages of said condenser, fan means for drawing air from said other ends of both the first and second sets of passages of said condenser, said air circulating arrangement being provided with normally closed valve means for stopping the flow of fluid, driving means for driving said drum and fan means, and delayed action thermal operating opening means for said valve means operable after the driving means and the heater have operated for a period.

4. A laundry dryer including a cabinet having a drum casing, a rotatable clothes drum within said casing, heating means for said casing, a condenser having a first set of passages communicating at one end with said casing and a second set of passages separated from but in heat transfer relationship with said first set, an air circulating arrangement comprising fluid inlet means for said casing and fluid outlet means for the second end of said first set of passages, said cabinet having second inlet means communicating with one end of said second set of passages and second outlet means communicating with the other ends of both the first and second sets of passages of said condenser, fan means for drawing air from said other ends of both the first and second sets of passages of said condenser, said air circulating arrangement being provided with normally closed valve means for stopping the flow of fluid, driving means for driving said drum and fan means, thermal operating opening means for said valve means, a second heater associated with said thermal means for opening said valve means, and dim ing means for first causing the operation of said first mentioned heater and driving means and then after the clothes are partly dried energizing said second heater to gradually open said valve means.

ReferencesCited in the file of this patent UNITED STATES PATENTS 2,369,366 ONeill Feb. 13, 1945 2,385,223 Moore Sept. 18, 1945 2,480,227 Derr Aug. 30, 1949 2,583,850 Kauflman Jan. 29, 1952 

